std :: cin ::和为什么一个换行仍然存在 [英] std::cin:: and why a newline remains
问题描述
参考资料为什么是控制台
Reference Why is the Console Closing after I've included cin.get()?
我使用 std :: cin.get()
#include<iostream>
char decision = ' ';
bool wrong = true;
while (wrong) {
std::cout << "\n(I)nteractive or (B)atch Session?: ";
if(std::cin) {
decision = std::cin.get();
if(std::cin.eof())
throw CustomException("Error occurred while reading input\n");
} else {
throw CustomException("Error occurred while reading input\n");
}
decision = std::tolower(decision);
if (decision != 'i' && decision != 'b')
std::cout << "\nPlease enter an 'I' or 'B'\n";
else
wrong = false;
}
我阅读了 basic_istream :: sentry 和 std :: cin :: get 。
我选择使用 std :: getline
,因为while循环执行两次,因为流不为空。
I chose instead to use std::getline
as the while loop is executing twice because the stream is not empty.
std::string line; std::getline(std::cin, line);
作为参考,我在上面发布的答案之一, std: :cin
用于读取字符, std :: cin :: get
用于删除换行符 \ n
。
As the reference I posted above states within one of the answers, std::cin
is utilized to read a character and std::cin::get
is utilized to remove the newline \n
.
char x; std::cin >> x; std::cin.get();
我的问题是为什么 std :: cin
在流上留下换行符 \\\
?
My question is why does std::cin
leave a newline \n
on the stream?
推荐答案
这是其默认行为,但可以更改。尝试此操作:
Because that's its default behavior, but you can change it. Try this:
#include<iostream>
using namespace std;
int main(int argc, char * argv[]) {
char y, z;
cin >> y;
cin >> noskipws >> z;
cout << "y->" << y << "<-" << endl;
cout << "z->" << z << "<-" << endl;
}
将由单个字符和换行符组成的文件\\ n),输出为:
Feeding it a file consisting of a single character and a newline ("a\n"), the output is:
y->a<-
z->
<-
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